利用渐渗系解析黄瓜心皮数基因CsCLAVATA3调控果实发育的多效性

Analysis of the pleiotropic effect of cucumber carpel gene CsCLAVATA3 regulating fruit development by near-isogenic lines

黄瓜心皮数基因CsCLAVATA3(CsCLV3)对提高黄瓜果实单果重和改良商品性状有重要意义。为了研究CsCLV3对黄瓜果实发育相关性状的遗传效应,以‘长春密刺’(CCMC)为轮回亲本,‘True Lemon’(TL)为供体亲本,获得CsCLV3近等基因系,利用SSR和GBS测序对筛选的3心皮纯合型与5心皮纯合型单株进行遗传背景分析,结果显示渗入片段位于1号染色体长臂。利用由310个单株构成的BC3F2群体对黄瓜心皮数目(CN)、果实长度(FL)、果实粗度(FD)、种子数量(SN)、成熟单瓜重量(FW)以及种子百粒重(HGW)进行表型分析及QTL定位分析。结果显示,CN、FL、FD、FW、SN、HGW均为双峰分布,符合1∶1的孟德尔分离定律,各性状与心皮数目极显著相关;近等基因系中5心皮纯合型的CN、FD、FW、SN高于3心皮纯合型,FL、HGW低于后者;在1号染色体心皮数连锁标记D1位置定位到CN、FL、FD、FW、SN和HGW的QTL,遗传贡献率分别为95.3%、55.2%、89.7%、83.2%、87.9%、93.9%,且均与CsCLV3共分离。本研究表明CsCLV3在调控黄瓜心皮数的同时对果实FL、FD、FW、SN、HGW具有调控多效性。

Carpel number gene CsCLAVATA3(CsCLV3) plays an important role in increasing single fruit weight and improving the commercial characters of cucumber. To study the genetic effects of CsCLV3 on cucumber fruit development-related traits, near-isogenic line of CsCLV3 was obtained by using ’Changchun Mici’(CCMC) as the recurrent parent and ’True Lemon’(TL) as donor parent. SSR and GBS sequencing were used to analyze the genetic background of the selected 3-carpel homozygous and 5-carpel homozygous plants. The results showed that the infiltrating fragment was located on the long arm of chromosome 1. Phenotypic analysis and QTL mapping of carpel number(CN), fruit length(FL), fruit thickness(FD), seed number(SN), fruit weight(FW) and hunderedgrain weight(HGW) of cucumber were analyzed by using BC3F2 population composed of 310 individual plants. The results showed that CN, FL, FD, FW, SN and HGW were all bimodal distribution, which conformed to the Mendel separation law at 1:1, and each character was significantly correlated with the number of carpels. In the near isogenic lines, the CN, FD, FW and SN of the homozygous type of 5 carpels were higher than those of the homozygous type of 3 carpels, while FL and HGW were lower than the latter. The QTL, genetic contribution rates of CN, FL, FD, FW, SN and HGW were located at D1 on chromosome 1, of which the genetic contribution rates were 95.3%, 55.2%, 89.7%, 83.2%, 87.9% and 93.9% respectively. These QTLs were co-segregated with Cs CLV3. This study showed that CsCLV3 had multiple regulation effects on FL, FD, FW, SN and HGW while regulating the number of cucumber carpels.